DESCRIPTION: (provided by the applicant): The long-term objective of our research program is to design situation- and/or site-specific strategies for the suppression of environmentally mediated infectious diseases. The immediate issue addressed here is to determine if the intensity of transmission of Schistosoma japonicum can be predictably diminished by using a mathematical model, based on both local data and general knowledge of the transmission cycle, to design effective interventions. The specific alms of this project are: 1.Model Development: to further develop our model of schistosomiasis transmission, based on exposure-related risk groups, to more effectively utilize site-specific field data typically collected in China as well as data on spatial factors relevant to disease transmission now easily obtained using GPS technology. 2. Use the Model for Design: to design effective control programs in four to six villages selected from two sites. The first phase of this work will be to collect the standard field data set in three villages in the Changqiu Mountains west of Chengdu to supplement that available from the Qionghai Lake villages with the objective of full site-specific calibration of the refined model. 3. Implement the Designs: we propose to implement the designs resulting from Specific Aim 2 and evaluate the results in these villages, if sustainable environmental interventions using traditional methods do not emerge, we will determine whether the impediments to success are rooted in inadequate knowledge, technological limitations, or agricultural practices.